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June 2, 1931. R. ECKSTEIN ELECTRICAL SOCKET Filed Aug. 27, 1927 INVENTORBY ATTORNEY Patented Junei, 193l- UNITED STATES PATENT or-nca or rmwmax, 1. '2.

men. sooner Application fled 27, 1887. Serial Re. 15,821.

a This invention relates to an improvement in electrical sockets andmore particularly to the type of socket used in mountin the miniaturebulbs of Christmas tree lig ting outfits and the like decorativedevices.

The object of the invention is to provide in a combination of the typewherein a number of lamp sockets are connected in series for association'with a power source, a means 19 whereby it is possible totest the lampswithout removing them from their respective sockets.

It is a further object of the invention to provide means permittingtesting any lamp 1 of the Christmas tree lighting outfit without the daner of burning out any of the other lamps w ich may be retained incircuit, durin thetestin operation.

, t is a fart er object to present a new and improved lamp socket forChristmas tree lighting outfits in which a short-circuiting 7 element isprovided havin means for preventing the increase of applied voltage onthe other lam s of the series.

26 An ad 'tional object is to provide in a lamp socket ashprt-circuiting means havin a simplified resistance unit ordinarilylaced in circuit whenever a lamp is remove from its socket.

. :0 Other objects of this invention will in part obvious and in parthereinafter pointed out.

The invention accordingly consists in the features of construction,combinations of elements, and arrangement of parts which will beexemplified in the construction hereinafter described, and of which thescope of ap plication will be indicated in the following claims.

In, the aceompanying'drawings, in which is shown one of the variouspossible illustrative embodiments of this invention,

Fig. 1 is a view showing a number of lamps mounted in an arrangement ofsockets connected in series in an assembly of the character ordinarilyused for Christmas tree lighting, and showing one of the sockets brokenaway to disclose-the invention in short-circuitmg osition.

60 Fig. 2 1s a longitudinal cross-sectional view secured to ascrew-bushing 18 Whic along line 2-2 of Fig. 1 disclosing theshortcircuiting device in inoperative position, as when a bulb has beeninserted into the socket. r

Fig. 3 is a cross-sectional view on line 3-3 showing the invention inplan.

Fig. 4 is an enlarged sectional view of the short circuiting element.

On the drawings, indicates an assembly of sockets 11 connected by theconductor 12 in series with each other and the connector plug 13, saidplug 13 being adapted to be inserted into a socket not shown) havingconnection, in turn, wit a source of power for lighting the lamps 14mounted in said sockets 11. The latter may be formed of any suitablewell known non-conducting material. Each socket isrovided with acylindrical recess 15 providing the openin 15a, and having a groove 16formed in awal thereof for receiving one end 17 of a conductor wire 12,this end 17 being fixedly may be either molded into or otherwise securedto socket 11. Said bushing 18 provides means for the reception of thescrew end19 of lamp 14, said screw end constituting one electricalcontact for said lamps.

An end 20 of a conductor 12 passes into recess 15 in socket 11 throughopening 21a in the end wall 21 of said recess, and is attached to acontact member 22 having secured thereto a disc 23 against which spring24 retained in said recess by wall 21 normally presses to force contactmember 22 into electrical contact with the projection 25 on lamp 14which constitutes the other electrical connection for said lamp. Thedisc 23, as shown in Fig. 4, may be retained on contact member 22 byheadin over the member 22 as at 26 to retain the disc against theshoulder 27 on the member 22.

The disc 23 comprises an insulating late. 28 around the edges of whichis secure the annular metallic ring 29 so positioned with respect tomember 22 and screw bushin 18 that, when the lamp 14 is withdrawn romscrew bushing 18, the metallic ring will contact with the rim 30 of thebushing 18. The

insulating plate 28 may be provided with a conducting medium thereacross which may I be so regulated in its application that -a T of lamp14. Another method for makingup such resistance units may be carried outby depositing on the insulating plate 28 metallic salts whichareefiected bylight, and then by an known photographic process, thesalts c anged to deposlt a metallic film on the plate, the amount ofdeposit being .con-

trollable by the time of exposure so that amount of metal deposited andtherefore the resistance of the plate may thereby be fixed at any knownquantity.

Since the head 26 and the shoulder 27 are brou ht into -direct contactwith the plate 28 and t e metallic ring 29 likewise has a direct contacttherewith, an eficient electrical connection is made thereacross sothat, when a bulb 14 is removed from the bushing 18, the

" circuit at the socket will still be maintained but, due to theresistance of plate 28, the

voltage as applied to any other one or more of the lamps in the circuitwill not be in:

creased; thus'avoiding injury to the remaining bulbs during a testingoperation or by accidental removal of a bulb while power is applied andcontributing to the long life of such devices. l 7

It is easily seen that if anyone lamp 1% adapted to meet the conditionsof practical use.

As various ossible embodiments might be made of the a ove invention, andas various changes might be made in the embodiment above set forth, itis to be understood that all matter herein set forth or shown in theaccompanying drawin is to be interpreted as illustrative and not in alimiting sense.

Having thus described my invention I claim as new and desire to. secureby Letters Patent:

1. In an electric socket, a bushing adapted to receive an electricelement, a spring pressed contact for said element in said socket, aninsulating disc mounted on said contact, said disc having a metallicfilm thereon making electrical connection with said contact and ametallic rin onthe outer periphcry of said disc making electricalcontact with said film.

2. In an electric socket, a bushing for an electric element, a contactin,said socket, a

disc mounted on said contact comprising an insulating member having athin coating of metallic conductin material thereon, secured to andmahng electrical connection with said contact, an annular ring securedto the perimeter of said member and in electrical contact withsaidcoating, and means for maintaining said ring normally in contactwith said bushing.

In testimony whcref l a my signature.

' RE EN ECSTEEN.

burns out, or in any other manner, becomes defective, the series circuitof'conductor 12 and connector lug 13 will be broken at that lamp. Then,partially screwing out the end 19 from soc et 11, ring 29 will hebrought into contact .With'the rim 30 of screw bush= v ing 18 and thecircuit completed between the two conductor ends 17 and 20 at thatsocket. If the defective lamp in the circuit be the defective one.

at that time found, the lamp so screwed out lamp 14 which'has thus beendisconnected, the other lamps will immediately light up, indicating thatthe lamp being handled is the lfthe defective one is not may be left inits released position and other lam s testedin the same manner until adefective one is found. Then screwing in the other bulbs will indicatewhether any other lam 14 is defective in like manner so that a testing 0eration will disclose not only a single 'de ective bulb but alldefective bulbs, home more than one is defective.

It will thus be seen that there isprovided V a device in which theseveral objects of thisinvention are achieved, and which is well

